Churn



NOV. 14, 31950 A W, HOLSTEIN ETAL 2,529,691

CHURN Filed Aug. 17, 1948 lll -III Patented Nov. 14, 1950 CHURN Alvin W. Holstein and Donald F. McCarron, St.

Louis, Mo., assignors to Knapp-Monarch Company, St. Louis, Mo., a corporation of Delaware Application August 17, 1948, Serial No. 44,778

8 Claims.

This invention relates to a churn and particularly one of the type having its churning mechanism driven by an electric motor.

One object of the invention is to provide a mechanical connection between a relatively highspeed motor such as one of the electric type and a churning impeller, said connection being of such nature that both rotary and reciprocating motions are transmitted to the impeller, the proportion of reciprocating to a rotary motion being automatically variable in accordance with the resistance offered to the impeller by the liquid being churned and the solids forming therein, the device being particularly adapted as a butter churn.

Another object is to provide a mechanical connection between the electric motor and the impeller which is comparatively simple and inexpensive to manufacture and eliminates the necessity of step-down spur gears, worm gears and the like.

Still another object is to provide a mechanical connection which consists of a rotating tube and a rod slidalole and rotatable therein, the rod having a double helical groove extending between lower and upper limits and provided 'with return ends, the tube carrying an element which travels in the groove whereby when there is no resistance to turning of the rod it will turn with the tube, and when there is resistance to its turning, rotary motion will be reduced and reciprocating motion increased more or less in accordance with the degree of resistance.

A further object is to provide means for imposing resistance to longitudinal movement of the rod relative to the tube in addition to that resistance oiiered by the liquid and/or solids iml pinged by an impeller driven by the rod.

Still a further object is to provide means for effecting increased rotary action of the impeller adjacent the upper end of the stroke of the impeller carrying rod to thereby secure maximum efliciency in the operation of the churn.

With these and other objects in view, our invention consists in the construction, arrangement and combination of the various parts of our device lwhereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in our claims and illustrated in the accompanying drawings, wherein:

Figure 1 is a vertical sectional View through a churn embodying our invention and showing a part of the mechanism in section.

Figure 2 is an enlarged sectional View of said mechanism.

Figure 3 is a sectional view on the line 3 3 of Figure 2.

Figure 4 is a perspective view of a connecting element used in my mechanism.

Figure 5 is an enlarged section of Figure 1 showing a mechanism that offers resistance to rotation of the impeller carrying rod of the churn, and

Figure 6 is a sectional view thereof on the line 5-6 of Figure 5.

On the accompanying drawing, we have used the reference numeral it to indicate a container for cream or the like to be churned. This container may be made of metal or glass, glass being shown in the dra-wing as transparency is desirable for the purpose of observing the contents during the churning operation. The container il) is preferably other-than-round in horizontal cross section to prevent too-free rotation of the liquid therein, hexagon or Octagon being a, suitable shape. Y

A cover l2 is provided for the container l0 and a motor housing lll-i5 is mounted thereon. Within the housing lll a motor is provided, the stator of which is indicated at i8 and the rotor of which is indicated at 20. The rotor 20 has a tubular shaft 22 extending therethrough which is journaled in upper and lower bearings 24 and 26. A cooling fan 28 for the motor is mounted on the tube 22 and draws air in through upper openings 32 in the housing portion i6 and discharges it through lower openings 30 in the housing portion I 3.

A-rod 34 is slidably and rotatably mounted in the tubular shaft 22 and has an impeller 36 on its lower end for the purpose of converting the cream inte butter. A seal 38 of Neoprene or the like is provided below the motor and supported by a housing dil extending downwardly from the container cover i2. A rubber washer 42 on the rod 34 Iwithin the housing in throws oli any grease by centrifugal force that might get past a sealing washer 82.

The rod Sri adjacent its upper end has a double helical groove or thread, the right-hand groove of which is indicated at 4a and the left-hand groove of which is indicated at 5t. At their upper ends these grooves are connected together by a return groove 52 that extends half way around the rod and at the lower end they are connected together by a similar return groove 54 that eX- tends half way around the rod.

A connecting element 56 is slidably and rotatably mounted in an opening EB of the tubular shaft 2,2. This element is in the form of a Ipin and has a blade 5D on its inner end retained for 3 travel in the grooves 4E, 5G, 52 and 54 by a leaf spring 62 held on the tube 22 by a screw 64.

In the upper end of the tube 22 a spring 66 is positioned between washers 44 and 46. The washer 46 is retained in the tube by means of a cross pin G8. The upper end of the rod 3!! has a central projection to bear at times against the washer 44.

In Figure 5 we show a means to provide a friction connection between the tubular shaft 22 and f the rod 34. This consists of friction washers 'I2 of rubber or the like and a felt lubricating washer 82, all stacked at the lower end of the tube 22. The washers i2 and S2 are notched as at 83 and 84 and a retainer washer 13 has arms 'i4 located in the notches and provided with inturned ends 16 entering openings in the tube 22 to hold the assembly in position. Due to the friction between the washers 'l2 and the rod 14 more cream resistance is required to decrease the rotation of the impeller and therefore its up and down movement is increased. Thus the proper balance between the two movements (rotation and reciprocation) can be controlled by the degree of friction.

Practical operation In the operation of our churn structure, assuming that cream has been placed in the container l0, and the rotor 20 and therefore the tubular shaft 22 is rotating, there will be very little resistance to rotation of the impeller by the cream. Assuming that there is no resistance whatever, then of course the impeller 36 will rotate at the same speed as the tubular shaft 22, especially since a friction drive connection is provided between the two consisting of the friction washers 12.

There is some resistance however between the impeller 36 and the cream. This resistance will tend to hold the speed of the rod 34 down to some fraction of the speed of the tube 22. Any difference in speed will cause the blade of the connecting element 5G to travel in the grooves 48-50-52-54, thus imparting reciprocation to the rod 34 and likewise up-and-down movement to the impelled 36 in relation to the container l0. The greater the resistance to rotation the more reciprocation will occur.

Working against the resistance to rotation referred to in the last paragraph however is the friction between the rod 34 and the washers 'l2 carried by the tube 22 and thereby rotated with it.

As resistance increases to the rotation of the impeller 35 due to the cream thickening and the butter solids forming therein the impeller rotations will be slowed down more and more as the churning operation proceeds. Since the threads 48 and 50 wind around the rod 34 for a considera-ble distance it will take a number of rotations of the rotor 3B to produce one reciprocation of the rod so that the mechanical connection which we disclose effects a slowing down action without the use of more complicated mechanisms such as step down gearing either of the spur or worm type.

In order to reduce the amount of reciprocating motion and increase the rotary motion of the impeller 3B the coil spring is used to retard the vertical movement of the rod 34 since the spring is compressed as the rod moves up against it, thus making the agitator or impeller turn the cream more vigorously at the top of the up-stroke. This increases the eiciency of the churning action. As the rod 34 moves downwardly the disc 44 strikes a shoulder 45 in the tube 22 so that the spring pressure is relieved in respect to the rod. The rod then continues in its downward movement, reverses and comes up to compress the spring 66 again thus repeating the operating cycles.

The mechanism disclosed for operatively connecting a churn impeller with a rapidly rotating motor is comparatively simple and compact. It is well adapted for the use of electric motors for churning butter and the like where a combination of rotary and reciprocating motion is desired for the impeller in order to get churning action at all desired elevations in the cream being churned.

The arrangement is such that rotary motion predominates when the cream is first being churned and reciprocating motion predominates during the final stages of churning, with various proportions of rotary-to-reciprocating motion occurring between these two extremes. The mechanism thereby automatically adapts itself to the condition of the liquid and solids at any stage in the churning operation and the result is the desired texture of finished product.

Some changes may be made in the construction and arrangement of the parts of our churn without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

We claim as our invention:

l. In an electric churn of the character disclosed, an electric motor, an impeller, and an operative connection between said motor and said impeller comprising a tubular shaft through the armature of said motor and a rod depending from the lower end of said tubular shaft. said rod having oppositely spiraled grooves with return portions at the upper and lower ends thereof, and a connecting element between said tubular shaft and said rod having a projection entering said grooves.

2. In a churn of the character disclosed, an impeller, a rapidly rotating tubular shaft, and an operative connection between said shaft and said impeller comprising a rod having one portion slidable and rotatable in said tubular shaft, said portion having oppositely spiraled threads with return portions at the upper and lower ends thereof, a connecting element between said shaft and said rod having a projection entering said threads said rod having another portion depending from said tubular shaft, said impeller being mounted on the lower end of said rod.

3. In a churn, a prime mover, an impeller, and an operative connection between said prime mover and said impeller comprising a tube and a rod, said rod having oppositely spiraled grooves with return portions at their ends, a connecting element between said tube and said rod having a projection engaging in said grooves, and packing means to seal said tube against entry of cream thereto around said rod, said means being also operable to reduce the relative movement between said rod and said tube.

4. In a churn of the character disclosed, a rotor, an impeller, and an operative connection between said rotor and said impeller comprising a tubular shaft and a rod rotated by said rotor, said rod having oppositely spiraled grooves with return portions at the upper and lower ends thereof, a connecting element between said tube and said rod having a projection in said grooves, and spring means to reduce the sliding of said rod in said shaft at the upper end only of the stroke of said rod.

5. In an electric churn of the character disclosed, an electric motor, an impeller, and an operative connection between said motor and said impeller comprising a tubular shaft and a rod slidable and rotatable therein and rotated by said motor, said rod having oppositely spiraled threads with return. portions at the upper and lower ends thereof, a connecting element between l0 said shaft and said rod having a lprojection entering said threads, a friction connection between said rod and said shaft, and spring means to reduce the sliding of said rod in said shaft `at the upper end only of the stroke of said rod.

6. Churning mechanism comprising a tubular motor driven rotating shaft, a rod reciprocable and rotatable therein, an impeller on said rod, said rod having opposite screw threads with connected ends, said tubular shaft having a pron having a projection into said screw threads, a spring in said shaft to be engaged and compressed by said rod and a shoulder limiting the expansion of said spring to the upper portion of the reciprocation of said rod.

8. Churning mechanism comprising a tubular shaft, a rod reciprocable and rotatable therein, an impeller on said rod, said rod having opposite screw threads with connected ends, said tube having a projection into said screw threads, a friction connection between said rod and said shaft, a spring in said shaft to be engaged and compressed by said rod and a shoulder limiting the expansion of said spring, said shoulder being located so that the major portion of the stroke of said rod relative to said tubular shaft occurs with the rod out of engagement with the spring.

ALVIN W. HOLSTEIN. DONALD F. MCCARRON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 529,764 Weeks Nov. 27, 1894 1,177,295 Beckner Mar. 28, 1916 1,186,526 Sears June 6, 1916 

